The present invention relates to a method of storing energy in cooling systems intended for cooling electronic equipment enclosed in preferably insulated spaces, and to an arrangement for storing energy in cooling systems used in this field.
With respect to electronic equipment that is placed outdoors in an insulated space, the purpose of a cooling system is to maintain the internal temperature of the space within a determined temperature range. Even though the ambient temperature may vary from xe2x88x9233 degrees C to +55 degrees C., it is often necessary to maintain the interior temperature of said space within a range of +5 degrees C. to +40 degrees C. with a mean temperature of +25 degrees C. over a long period of time. It is not possible to maintain a temperature beneath +40 degrees C. in a space when the outdoor temperature may be above +40 degrees C., solely by using heat exchangers or ventilation units that include filters. Normally, the higher temperature limit can only be maintained with the aid of an active cooling circuit that includes a compressor. FIG. 1 illustrates how different cooling systems that include ventilation units, heat exchanger units or cooling compressor units can be used for different temperature regions at varying outdoor temperatures.
It is also known to use for cooling purposes small containers that are filled with different sodium sulphate mixtures or paraffins that are able to pass from one phase to another phase such as a solid phase to a liquid phase at given temperatures, so as to deliver heat. These containers can be placed in spaces that house electronic equipment and use as reserve cooling means in the event of a breakdown in the standard cooling system.
In the event of a variation in the outdoor temperature over a period of one calendar day, such as a temperature difference between day and night, it is possible to store energy passively with the aid of an energy storage facility and use this facility to equalise temperature variations in a space that houses electronic equipment. By storing energy in an equipment cooling system, variations in outdoor temperature can be used conveniently for cooling the equipment. A cooling system that uses a cooled air flow to cool electronic equipment in a closed space may include a heat exchanger that cools the air flow with a passing air flow that arrives directly from outside said space or that has passed through a unit in which said energy is stored. In this regard, energy may be stored in a system of mutually combined plates on which several bodies containing salt solutions are disposed, said plates and bodies being enclosed in a container arranged in the vicinity of the heat exchanger or in the vicinity of some part of said heat exchanger and allowing outdoor air to flow therethrough.
The invention will now be described in more detail with reference to preferred embodiments thereof and also with reference to the accompanying drawings.